The Best Ways to Bulletproof Your Immune System

Like any good defense network, your immune system needs regular maintenance to stay in fighting shape. Here's how to keep it battle-ready.

The Best Ways to Bulletproof Your Immune System

Like any good defense network, your immune system needs regular maintenance to stay in fighting shape. Here's how to keep it battle-ready.

Like most guys, you probably don’t give your immune system a second thought. It hums along 24 hours a day, mounting savage attacks against viruses and bacteria, without ever troubling you with the intricacies of its functioning—until, of course, that functioning breaks down.

But here’s the thing: Those breakdowns—be they colds, sore throats, or bacterial infections—are often our own doing. “The more we learn about immune function, the more we realize that everything affects it,” says Ronald Glaser, Ph.D., professor of molecular virology, immunology, and medical genetics at Ohio State University.

Stress, lack of sleep, poor dietary habits, too little exercise, even an extra hour in the sun, can severely limit your immune response. So can age. “Your immunological peak is over by 35,” says Monika Fleshner, Ph.D., associate professor in the department of integrative physiology and a member of the Center for Neuroscience at the University of Colorado at Boulder. But you can bolster your battlements—and save those days off for summer vacation. Proper diet, exercise, and hygiene are all good starts, but recent studies have ID’d a handful of new ways to keep you out of the doctor’s office. And as you’re taking steps to bulletproof your body, be sure to adopt the 100 Easiest Ways to Be a Healthier Man Right Now.

1
Have Sex

Research shows that sexual activity one or two times a week increases the production of IgA, an infection-fighting protein that prevents harmful microorganisms from binding to the lining of your digestive and respiratory tracts. No one to share the sheets with? Hugs, handshakes, dog petting, massages, and soothing music will also do the trick. (For the record, having sex is also one of our 15 easy ways to look a decade younger.)

“Psychosocial variables effect IgA, which is the most prevalent of the major antibodies in our system,” says Carl Charnetski, Ph.D., professor of psychology at Wilkes University, in Pennsylvania, and author of Feeling Good Is Good for You: How Pleasure Can Boost Your Immune System and Lengthen Your Life.

2
Get Promoted

Researchers at Carnegie Mellon University recently found that lower socioeconomic status was associated with higher levels of three stress hormones (cortisol, epinephrine, and norepinephrine) proven to suppress immune function. A good way to move up in the corporate world, according to a report in the Journal of Applied Psychology, is to favor “ingratiation” over “self-promotion” during job interviews. In short, kiss up (by, say, agreeing with a supervisor’s opinions even if you don’t wholeheartedly agree with them) instead of pushing your own qualifications for the new position. For great tips on navigating the corporate world, check out 25 Ways the Smartest Men Get Ahead at Work.

3
Laugh It Off

Scientific journals are rife with studies linking stress to almost every modern malady—from heart disease to the common cold. Research out of the University of Maryland, however, has identified one of the best ways to combat it: laughter.

The researchers found that watching clips from funny movies (including, we kid you not, the classic Farrelly Brothers film Kingpin) increased blood flow—and, therefore, the circulation of immune-system cells—by 22 percent. Stressful clips, such as battle scenes from a war movie, on the other hand, caused blood vessels to constrict, decreasing blood flow by 35 percent. Looking for a good time? Here are the 20 Best Ways to Relive Your 20s.

4
Pop Some ‘Shrooms

“Though the science is still developing, some mushrooms appear to prime the immune system,” says Susan Percival, Ph.D., professor of nutritional science at the University of Florida. Mushrooms contain active compounds that boost the production of “killer” cells that scavenge the body for germs. Asian varieties, such as shiitake and reishi, confer the most benefit, says Percival, who suggests eating half an ounce, cooked or raw, at the first sign of a cold and then every day afterward until symptoms subside. For more great health tips, don’t miss the 20 Ways to Never Get Sick at Work.

5
Catch Some Rays

Excessive sunlight can hamper immune function, but a little can boost it, say researchers at the Sunlight, Nutrition, and Health Research Center, in San Francisco. In a meta-analysis of cancer studies, they found that moderate sun exposure prompts the body to produce enough vitamin D to regulate immune function and fight a range of cancers, including colon, lung, and prostate. Thirty minutes a day should do the trick, although those in northern latitudes might want to supplement their diet with vitamin D once winter rolls around. Need to get out more? It may be time for some of the Best Exotic Vacations in the World.

6
Sleep On It

Getting less than eight hours of sleep is like leaving your body’s front door open—just about anything can waltz in and wreak havoc. That’s what researchers at the University of California at Los Angeles found when they studied blood samples from 30 individuals both before and after a night of sleep deprivation. Losing just a couple of hours is enough to increase inflammation, causing an overreaction of the immune system that has been linked to an increased risk of cardiovascular disease, arthritis, and diabetes. If you’re having trouble getting your daily amount of Z’s, we’ve got your back with the 10 Ways to Sleep Better Tonight—Guaranteed.